1. Field of the Invention
This invention relates to a valve for use in various types of hydraulic apparatus.
2. Description of the Related Art
The inventor of the present invention has filed an application for patent on a novel valve, which has been disclosed in Japanese Patent Laid-Open No. 61-228178 and Japanese Patent Publication No. 3-61870.
The valve according to the above-mentioned disclosed invention has a feature that the valve body can be easily opened and closed with a small force with respect to a liquid at a relatively high pressure, and that a speed reduction is effected when the valve body is opened and closed so as to protect the valve seat, etc. from impact, thereby providing the valve with a long service life.
However, the valve of the above-mentioned disclosed invention still has a problem that the buffer effect when the valve body is opened and closed is not adequate, thereby making it impossible to obtain a sufficiently long service life for the valve. Further, due to this inadequate buffer effect, it is impossible to open and close the valve at a minimum speed so as to enable the associated hydraulic apparatus to perform a minimum-speed starting. Nowadays, such a minimum-speed starting or stopping is a requirement for various types of hydraulic apparatus.
The present invention has been made with a view to solving the problems mentioned above. It is accordingly an object of the present invention to provide a valve which is capable of exerting a sufficient buffer effect when the valve body is opened and closed so as to enable it to be opened and closed at a minimum speed, thereby enabling various types of apparatus to which this valve is applied to perform a minimum starting and stopping.